Electric lamp and manufacturing method

ABSTRACT

The electric lamp has a lamp vessel ( 10 ) having a pinch ( 12 ) mounted in an outer envelope ( 1 ) by means of a clamping member ( 20 ) of metal sheet which is present on the pinch ( 12 ). The clamping member ( 20 ) has an open loop ( 21 ) which extends in a direction transverse to the broad side faces ( 13, 14 ) of the pinch ( 12 ). A still open clamping member ( 20 ), when present around the pinch ( 12 ), can easily be fastened by plastically deforming a specified region of the member by the method of the invention.

The invention relates to an electric lamp comprising:

-   -   an outer envelope carrying a lamp cap;    -   a gastight closed glass lamp vessel with an axis and a pinch        around the axis, mounted in the outer envelope,    -   which pinch is provided with a first and a second relatively        broad side face, facing away from one another and having a        smallest interspacing, and with, between the broad side faces, a        first and a second, relatively narrow side face having a width        that is greater than said smallest interspacing of the broad        side faces;    -   an electric element in the lamp vessel, connected to current        conductors which issue from the lamp vessel to the exterior;    -   electrical conductors connected to the lamp cap, entering the        outer envelope, and connected to respective current conductors;        and    -   a clamping member bent from metal sheet, gripping around the        first narrow side face, and pressing against the broad side        faces to hold the lamp vessel, which clamping member is held        positioned in the outer envelope.

The invention also relates to a method of manufacturing an electric lampprovided with a gastight closed glass lamp vessel with a pinch, whichpinch has a first and a second relatively broad side face and relativelynarrow, smaller side faces,

-   -   by which method a clamping member, bent from metal sheet, is        fitted on the pinch, which member will grip around one of the        narrow side faces and will press against the broad side faces to        hold the lamp vessel tight.

An embodiment of such an electric lamp is available on the market.

In the known lamp, the clamping member has the same shape as theclamping member used on the pinch of an H2 automotive lamp, where itserves as a contact for the electrical and mechanical connection of thelamp in a headlight.

The clamping member of the known lamp has a strip of metal sheet foldeddouble, the end portions of which are bent apart, with ends that pointat each other at an angle so as to form a dovetail-shaped space,accommodating the cross-sectionally dovetailed portion of the pinch. Theclamping member thus has a symmetrical shape and extends with its foldedportion to the side of the pinch, parallel to the broad faces. A currentconductor is welded to the folded portion, and tongues are present onthe folded portion in line with the lamp vessel, in between whichtongues an electrical conductor is welded to keep the clamping member inplace and to make contact with the electric element.

A drawback of the known lamp is that the lamp vessel with the clampingmember is so bulky that it is difficult or even impossible to insert thevessel in the outer envelope if it has a relatively large pinch.

It is a first object of the invention to provide an electric lamp of thekind described in the opening section with a construction that makes thepresence of a lamp vessel with a relatively big pinch possible.

A second object of the invention is to provide a manufacturing method ofthe kind described in the opening section that can be carried outquickly and easily.

According to the invention, the first object is realized in that theclamping member has an open loop with a base having a first and a secondleg, the first leg extending from the base transversely to the broadside faces along the first narrow side face and hooking behind the firstbroad side face, and the second leg extending at a distance from thefirst leg to the second broad side face and pressing tightly against itwhile enclosing an acute angle therewith.

The clamping member of the lamp according to the invention prevents thatthe dimension of the interior of the lamp is increased by the clampingmember in the widthwise direction of the pinch. The clamping memberextends mainly transversely to the broad faces and consequently itsshape, unlike that of the known lamp, is asymmetrical. In this way it ispossible, when assembling the lamp, to insert the lamp vessel with theclamping member through an opening, which is usually round, into theouter envelope, even if the broad side faces are relatively wide.

It is advantageous if the second leg has a curve with which it pressesagainst the second broad side face. This counteracts the risk of, forexample, a burr on the second leg making scratches in the second broadside face during mounting of the clamping member, which may lead tofracture.

For a firm grip on and a defined position of the pinch it isadvantageous if the first leg extends along the first broad side face tothe axis to form a first and, at a distance from this, a second axialcontact line with the first broad side face, and if the second leg has athird contact line against the second broad side face, which, whenprojected perpendicularly on the first broad side face, lies between thefirst and the second contact line.

The clamping member can be bent open when it is mounted on the pinchand, after being fitted around the pinch, be released again to fix thepinch in position.

In a favorable embodiment, the second leg has a bend near the base, fromwhere the leg runs at an acute angle to the second broad side face. Thisembodiment makes it easy to mount the clamping member on the pinch. Theclamping member can then be “open” when fitted around the pinch, so thatit can be positioned completely or almost completely without tension andwith little or no friction. Subsequently, the second leg of the clampingmember is forced near the base towards the first leg, causing a plasticdeformation in that spot and providing an elastic deformation in thesecond leg, away from the base. Due to the elastic deformation, theclamping member subsequently keeps the pinch fixed in position. Theplastic deformation prevents the second leg from springing back too muchafter the treatment and causing the pinch to be insufficiently clamped.

For the realization of the local plastic deformation it is favorable forthe base to be relatively stiff. In this way, the plastic deformation isrealized mainly by a change of the direction in which the second legrests on the base. A relatively stiff base may be realized, for example,by the presence of an elongated embossment in the base from leg to leg.

It is, however, easy to arrange that the legs link up with the base onbending lines, and that the base is substantially flat.

In a favorable embodiment, the clamping member has a tongue to which asupport is fixed which keeps the clamping member in position. Thesupport may be one of the electrical conductors. Alternatively, thesupport may be a rod connected to the outer envelope, for example, ifthe outer envelope is connected to, for example fused to, a mount, or arod embedded in the seal of the mount.

It is favorable if the tongue is an end portion of the first leg,transverse to the first broad side face. The tongue is then in a veryfavorable position for realizing the connection to the support.

In a favorable embodiment, the outer envelope is connected to a mountprovided with a seal from which the electrical conductors enter theouter envelope, the pinch is between the electrical conductors,transverse to the seal, and the tongue is fixed to one of the electricalconductors as a support.

The advantage of this embodiment is that the construction of thecontents of the outer envelope in the axial direction is very short.

The lamp may be an incandescent lamp, for example a halogen incandescentlamp, in which the electric element is an incandescent body in ahalogen-containing gas, but it may alternatively be a discharge lamp, inwhich the electric element is a pair of electrodes in an ionizable gas.The lamp vessel may be made of quartz glass or hard glass. The outerenvelope may be closed gastight and evacuated, or be filled with gas,but it may alternatively be in open connection with the surroundings ofthe lamp.

The clamping member may be made of brass or steel, for example softspring steel, or, if it is mounted in its final shape on the pinch, ofhardened spring steel.

The lamp cap may have any shape, for example provided with contact pins,or be of the Edison or bayonet type.

The second object of the invention is realized in that

-   -   a clamping member is used that has an open loop with a base        having a first and a second leg, the first leg extending away        from the base transversely to the broad side faces, along a        narrow side face and hooking behind the first broad side face,        and the second leg being at a distance from the first one and        having a bend near the base, from where it runs at an acute        angle towards the second broad surface, and in that    -   the second leg, when in the presence of the pinch, is        plastically deformed near the base to ensure a clamping contact        of the second leg with the second broad side face of the pinch.

Embodiments of the electric lamp and the method according to theinvention are shown in the drawing, in which

FIG. 1 shows an embodiment in side elevation, partly in cross section;

FIG. 2 shows a detail taken on the line II-II in FIG. 1;

FIG. 3 shows the detail of FIG. 2 during manufacture;

FIG. 4 shows another embodiment of the clamping member;

FIG. 5 shows a variant as in FIG. 2.

Corresponding components have been given the same reference numeralsthroughout the Figures.

The electric lamp of FIG. 1 has an outer envelope carrying a lamp cap 2.The outer envelope 1 has an aluminized mirror 7 and a mount 5. The mount5 has a seal 6, in which a support 4 is embedded. A gastight closedglass lamp vessel 10, made of quartz glass in the Figure, with an axis11 and a pinch 12 around the axis 11, is mounted in the outer envelope1. The pinch 12, see also FIGS. 2 and 3, is provided with a first 13 anda second relatively broad side face 14, facing away from one another andhaving a smallest interspacing, and with, between the broad side faces13, 14, a first 15 and a second, relatively narrow side face 16. Thewidth of the narrow side faces 15, 16 is greater than the smallestinterspacing of the broad side faces 13, 14. The pinch 12 is a so-termedlimited pinch, that is to say, a pinch that is formed by heating a glasstube to the softening point and pinching it up. During pinching,however, not only the broad side faces are shaped with pinch blocks, butthese blocks also shape folds formed at the sides of the broad sidefaces by flattening them to form the narrow side faces.

An electric element 17, in the Figure a tungsten incandescent body in aninert gas that comprises HBr, is mounted in the lamp vessel 10,connected to current conductors 18 issuing from the lamp vessel 10 tothe exterior. Electrical conductors 3, which are connected to the lampcap 2, enter the outer envelope 1 and are connected to respectivecurrent conductors 18. A clamping member 20, bent from metal sheet,grips around the first narrow side face 15 and presses against the broadside faces 13, 14 to hold the lamp vessel 10. The clamping member 20 isheld positioned in the outer envelope 1 by support the 4. The pinch 12of the lamp vessel 10 and the seal 6 of the mount 5 are axially spacedapart.

The clamping member 20, see also FIGS. 2 and 3, has an open loop 21 witha base 22 having a first 23 and a second leg 24, the first leg 23extending from the base 22 transversely to the broad side faces 13, 14,along the first narrow side face 15 and hooking behind the first broadside face 13. The second leg 24 extends at a distance from the first one23 to the second broad side face 14 and presses tightly against it. Thesecond leg 24 encloses an acute angle with said side face 14.

The second leg 24 has a curve 25, see FIG. 3, with which it pressesagainst the second broad side face 14.

The first leg 23 extends along the first broad side face 13 to the axis11 to form a first 26 and, at a distance from the first one, a secondaxial contact line 27 with the first broad side face 13. The second leg24 has a third contact line 28 against the second broad side face 14,which, when projected perpendicularly on the first broad side face 13,lies between the first 26 and the second contact line 27.

The second leg 24 has a bend 29 near the base 22, from where the leg 24runs at an acute angle to the second broad side face 14.

In FIG. 3, the “open” clamping member 20 is fitted around the pinch 12,but it still has to be pinched shut through plastic deformation of thesecond leg 24 near the base 22, between the bend 29 and the base 22, byforcing it towards the first leg 23.

In the embodiment of FIG. 4, the base 22 of the clamping member 20 isrelatively stiff. The legs 23, 24 link up with the base 22 on thebending lines 30, and the base 22 is substantially flat.

The clamping member 20, FIGS. 1, 2, 3, 4 and 5, has a tongue 31 to whichthe support 4 in FIG. 1 is fixed to keep the clamping member 20 inposition. The tongue 31 is an end portion 31 of the first leg 23, whichis transverse to the first broad side face 13.

It is not only favorable for the stability of the lamp vessel 1 in theclamping member 20 that the first leg 23 extends along the first broadside face 13 to the axis 11, but also for the centric positioningpossibility of the lamp vessel 10 in the outer envelope 1, as shown inFIG. 1, where the centrally located support 5 is fixed to the tongue 31on the first leg 23.

This is also reflected in FIG. 5. In this Figure, the pinch 12 istransverse to the seal 6, between the electrical conductors 3. Thetongue is welded to a thick conductor 3 which has a relatively greatstiffness because of its diameter. FIG. 5 shows that a centric positionof the pinch 12 is also realized in the drawn configuration. Anadvantage of the arrangement of the pinch 12 between the electricalconductors is that the distance between the pinch 12 and the seal 6 canbe minimal, so that the lamp can have a small axial dimension.

The tongues 31 of the previous Figures have elongated embossments 32,which are transverse to the support 4 or the electrical conductor 3fixed thereto. The advantage of the embossments 32 is that they make apoint contact with the support 4 and the conductor 3, so that it is easyto make a good-quality resistance weld.

1. An electric lamp comprising: an outer envelope (1), carrying a lampcap (2); a gastight closed glass lamp vessel (10) with an axis (11) anda pinch (12) around the axis (11), mounted in the outer envelope (1),which pinch (12) is provided with a first (13) and a second relativelybroad side face (14), facing away from one another and having a smallestinterspacing, and with, between the broad side faces (13, 14), a first(15) and a second, relatively narrow side face (16) having a width thatis greater than said smallest interspacing of the broad side faces (13,14), an electric element (17) in the lamp vessel (10), connected tocurrent conductors (18) which issue from the lamp vessel (10) to theexterior; electrical conductors (3) connected to the lamp cap (2),entering the outer envelope (1) and connected to respective currentconductors (18); and a clamping member (20) bent from metal sheet,gripping around the first narrow side face (15), and pressing againstthe broad side faces (13, 14) to hold the lamp vessel (10), whichclamping member (20) is held positioned in the outer envelope (1),characterized in that the clamping member (20) has an open loop (21)with a base (22) having a first (23) and a second leg (24), the firstleg (23) extending from the base (22) transversely to the broad sidefaces (13, 14) along the first narrow side face (15) and hooking behindthe first broad side face (13), and the second leg (24) extending at adistance from the first leg (23) to the second broad side face (14) andpressing tightly against it, while enclosing an acute angle therewith.2. An electric lamp as claimed in claim 1, characterized in that thesecond leg (24) has a curve (25) with which it presses against thesecond broad side face (14).
 3. An electric lamp as claimed in claim 1,characterized in that the first leg (23) extends along the first broadside face (13) to the axis (11) to form a first (26) and, at a distancethere from, a second axial contact line (27) with the first broad sideface (13), and the second leg (24) has a third contact line (28) againstthe second broad side face (14) which, when projected perpendicularly onthe first broad side face (13), lies between the first (26) and thesecond contact line (27).
 4. An electric lamp as claimed in claim 3,characterized in that the second leg (24) has a bend (29) near the base(22), from where the leg (24) runs at an acute angle to the second broadside face (14).
 5. An electric lamp as claimed in claim 4, characterizedin that the base (22) is relatively stiff.
 6. An electric lamp asclaimed in claim 6, characterized in that the legs (23, 24) link up withthe base (22) on bending lines (30), and the base (22) is substantiallyflat.
 7. An electric lamp as claimed in claim 1, characterized in thatthe clamping member (20) has a tongue (31) to which a support (4) isfixed, which support keeps the clamping member (20) in position.
 8. Anelectric lamp as claimed in claim 7, characterized in that the tongue(31) is an end portion (31) of the first leg (23) which is transverse tothe first broad side face (13).
 9. An electric lamp as claimed in claim7, characterized in that the outer envelope (1) is connected to a mount(5) provided with a seal (6) from which the electrical conductors (3)enter the outer envelope (1), the pinch (12) is between the electricalconductors (3) and transverse to the seal (6), and the tongue (31) isfixed to one of the electrical conductors (3) as a support (4).
 10. Amethod of manufacturing an electric lamp provided with a gastight closedglass lamp vessel (10) with a pinch (12), which pinch (12) has a first(13) and a second, relatively broad side face (14) and relatively narrowside faces (15, 16), by which method a clamping member (20), bent frommetal sheet, is fitted on the pinch (12), which member will grip aroundone of the narrow side faces (15, 16) and will press against the broadside faces (13, 14) to hold the lamp vessel (10) tight, characterized inthat a clamping member (20) is used that has an open loop (21) with abase (22) having a first (23) and a second leg (24), the first leg (23)extending from the base (22) transversely to the broad side faces (13,14) along one of the narrow side faces (15, 16) and hooking behind thefirst broad side face (13), and the second leg (24) being at a distancefrom the first one (23) and having a bend (29) near the base (22), fromwhere the leg (24) runs at an acute angle towards the second broad sideface (14), and in that the second leg (24), when in the presence of thepinch (12), is plastically deformed near the base (22) to ensure aclamping contact of the second leg (24) with the second broad side face(14) of the pinch (12).